The number of Americans with high-speed Internet access at home continues to grow —- except among African-American and low-income households.

A report from the Pew Internet & American Life Project says that the percentage of Americans with broadband Internet service at home jumped from 47 percent last year to 55 percent in May. That percentage crossed the 50 percent mark last September.

Only about one-fourth of households with annual incomes less than $20,000 have fast Internet service, a slight drop from last year.

And among African-American households, home broadband usage stood at 43 percent in May, about flat from a year earlier.

By comparison, about 57 percent of whites and English-speaking Hispanics have high-speed access, up about 10 percentage points from a year earlier.

The stagnant numbers among low-income and black households could be indicative of a new type of "digital divide" between the societal haves and have-nots in the new Internet age, said John Horrigan, associate director of research at the nonprofit Pew project.

Instead of the divide of a decade or so ago —- between those Americans who had home Internet service of any kind and those who didn't —- "there's a potential for" a new divide centered on high-speed service and all the innovations that come with it, Horrigan said.

Internet users who don't have high-speed Internet access could miss online entertainment or video-based learning programs on the Web, for instance, or find it hard to access government documents or other necessities electronically.

Low-income households are a tougher sell for high-speed broadband service, Horrigan said.

Some low-income Americans simply may not see any need for high-speed Web access. Others may not be able to justify spending an average of $34.50 each month on such service.

And some simply may not be able to get high-speed service in their neighborhoods, especially if they live in rural areas.

The biggest factor is the cost, Horrigan said.

According to the Pew survey, only about 10 percent of non-broadband users said high-speed Internet service wasn't available to them. About 35 percent said that price was a barrier.

Among other findings:

> 27 percent of Americans, mostly low-income elderly adults, say they do not use the Internet at all.

> 15 percent of Americans have slower dial-up Internet service, down from about 30 percent four years ago.

> 34 percent of Internet users said they've gone online away from home using a wireless Wi-Fi connection on their laptop computer. Among those, 64 percent said they used a free service.